Apparatus and processes for compressing and/or biodigesting material

ABSTRACT

Apparatus and process for compressing moisture containing material including a pair of opposed rolls for receiving and advancing the material therebetween to apply rolling load thereto to compress the material and remove at least a portion of said moisture therefrom, and differential means for causing one of said rolls to rotate at a lower speed than the rolling speed of the other of the rolls, the differential rolling speeds developing friction between the rolls causing the rolls to be heated and apply heat to said material to further remove moisture therefrom, to cause the compressed material to adhere to the one roll and to cause the removed moisture to adhere to the other roll, also alone and in combination, apparatus and process of decomposing organic material such as animal biomass by the action of aerobic microorganisms in the presence of oxygen, including introducing the organic material into a container having an end adapted to receive the organic material and an output end adapted to discharge the organic material, introducing a medium containing oxygen into the container to facilitate decomposition of the organic material by action of said microorganisms, and advancing the organic material through the container and upon decomposition of the organic material discharging the decomposed organic material out the output end of the container.

This is a division of application Ser. No. 792,026, filed Oct. 28, 1985,now U.S. Pat. No. 4,683,814, issued Aug. 4, 1987.

BACKGROUND OF THE INVENTION

This invention relates generally to apparatus and processes forcompressing moisture containing material and more particularly toapparatus and processes for reducing the moisture content of moisturecontaining material such as wood or woody biomass, e.g. wood chips orgreen wood chips, pulp chips, hogged wood, sawdust, woodflour, woodbark, wood fiber pulp, lignin, and the like; vegetable/fruit biomass,e.g. cornstalks, peat, and the like; animal/fowl biomass, e.g. manureand the like; paper mill sludge; industrial mill sludge; municipalsewage sludge; coal slurry and the like; and for enhancing theproduction of ethanol and methanol.

As is known to those skilled in the moisture removal or reduction art,the removal or reduction of moisture from the foregoing examples is donefor a variety of purposes. For example, moisture is removed from wood orwoody biomass to convert the biomass to fuel, to enhance a pulping orpaper making process, to produce fertilizer from animal/fowl biomass,and to reduce the moisture content of certain wood biomass, such as woodbark or other residue from a pulping or paper making process, prior tothe typical burning of such residue for riddance as such residue isknown to unwantedly rapidly accumulate in large quantities.

Due to the constant dwindling of the world's known oil reserves, it ishighly desirable to be able to use wood, vegetable/fruit and animal/fowlbiomasses as substitutes for oil and as an energy saving fuel source,such as boiler fuel. This is due primarily to their cheapness of costand plentiful availability. However, as is known to those skilled in theart, and with regard to wood biomass as an example, the primarydeterrent to the use of wood chips or green wood chips and the like foran energy saving fuel source, such as a boiler fuel, is the naturallyhigh moisture content of the wood chips. Generally, the moisture contentis so high that the wood chips cannot be burned efficiently as boilerfuel but first must be pre-dried. Such pre-drying unwantedly consumesenergy and in most instances the amount of energy consumed in pre-dryingvirtually renders the use of wood chips as a fuel saving energy source aself-contradiction.

By way of further example, the two basic methods known for reducingmoisture in wood biomass, e.g. wood chips for fuel such as boiler fuel,are: (i) heat energy to vaporize the moisture, (ii) mechanical energy tosqueeze the moisture out. A variety of mechanical apparatus and methodsof dewatering of wood chips, pulping rejects and bark are known to theart such as bark presses, roll presses, jaw presses and screw presses.These apparatus have not been highly successful in removing or reducingthe moisture content of wood chips, particularly the bound water, i.e.the water held by physical/chemical bonding within the cell wall orcellular structure of wood biomass. It has been stated by John G.Haygreen, in his article entitled, "Potential for Compression Drying ofGreen Wood Chip Fuel," FOREST PRODUCTS JOURNAL, Vol. 31, No. 8, August1981, "It should not be expected to lower the moisture content of woodbelow 30% by mechanical means." As is further known to those skilled inthe art, the use of wood chips as an economically feasible source ofboiler fuel generally requires that the moisture content of the woodchips be reduced below 30%.

Accordingly, there exists a great need in the art for apparatus andprocesses for reducing the moisture content of moisture containingmaterials such as the above-noted wood, vegetable and animal biomassesbelow that which may be achieved by presently known methods andapparatus for moisture removal or reduction, and a great need in the artfor apparatus and process for enhancing the production of ethanol andmethanol.

Further, this invention relates generally to apparatus and processes forbiodigesting, decomposing, or composting organic material, such as forexample animal biomass, e.g. manure, cow manure, and the like. As isknown to those skilled in the art, animal biomass, such as cow manureand the like, decomposes naturally and it is advantageous to facilitateor accelerate such decomposition for use as organic fertilizer or soilconditioner. While many biodigesting, composting, or decomposingapparatus and processes are known to the art, because all such prior artapparatus and processes have various deficiencies of operation orattendant unwanted expensiveness of operation, they have been found tobe not as useful as the processes and apparatus of the present inventionfor biodigestion. Accordingly, there is a need in the art for improvedprocesses and apparatus for the biodigestion, decomposition, orcomposting of organic materials such as animal biomass, e.g. cow manureand the like, and further, if desired or required, for apparatus andprocess for reducing the moisture content of such decomposed orcomposted organic material, e.g. cow manure and the like, to furtherenhance its use as an organic fertilizer or organic soil conditioner orto further enhance its ease of transportation and use through reducedmoisture content.

SUMMARY OF THE INVENTION

Moisture is removed from the above-noted moisture containing materialsby advancing the material between opposed rolls operating at differentspeeds to compress the material and remove moisture therefrom, and tocause friction to develop between the rolls causing the rolls to beheated and apply heat to the compressed material to remove additionalmoisture therefrom, to cause the moisture to adhere to the roll rotatingat the higher rate and to cause the compressed material to adhere to theroll rotating at the slower rate. The rolling load may be sufficientlygreat to also provide shearing action to material having cellularstructure to rupture such cellular structure and remove bound moisturecontained therein. The moisture may be wiped from the higher rotatingroll for collection and the compressed material may be wiped from theslower rotating roll for collection and use as taught herein.

Prior to the removal of moisture from the above-noted moisturecontaining materials, such materials, particularly upon such materialsbeing organic matter such as animal biomass, e.g. manure, may bebiodigested or composted to decompose the material into, for example inthe case of animal biomass, e.g. manure, into organic fertilizer or soilconditioner. Subsequently, if desired or required, such decomposedmaterial may have moisture contained therein removed by the presentinvention as summarized above.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatical illustration of rolling apparatus embodyingthe present invention and useful for practicing the process of thepresent invention;

FIG. 2 is a side elevational view of alternate apparatus embodying thepresent invention and including feed finger apparatus for facilitatingadvancement of moisture containing material between the rolls and whichalternate apparatus also are useful for practicing the process of thepresent invention;

FIG. 3 is a top plan view of the apparatus of FIG. 2 but with the hopperand upper roll removed for convenience and clarity of presentation;

FIG. 4 is a side elevational view of further alternate apparatusembodying the present invention;

FIG. 5 is a diagrammatical illustration of a biodigester embodying thepresent invention;

FIG. 6 is a cross-sectional view taken generally along the line 6--6 inFIG. 7 and in the direction of the arrows;

FIG. 7 is a diagrammatical illustration of an alternate embodiment ofthe present invention upon the biodigester of FIG. 6 being provided withthe air tube(s) illustrated diagrammatically in FIG. 7; and

FIG. 8 is a diagrammatical illustration of apparatus and process of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is illustrated diagrammatically apparatusembodying the present invention and indicated by general numericaldesignation 10. The apparatus includes a pair of opposed rolls 12 and 14for advancing moisture containing material therebetween, such as forexample the wood chips illustrated diagrammatically by referencenumerals 16, to compress the material and remove at least a portion ofthe moisture therefrom; the wood chips 16 may be fed from a suitablehopper 18 which may be any one of several known to those skilled in theart. The rolls 12 and 14 may be rolls of any one of several rollingmills known to the art and their proper selection will become apparentfrom an understanding of the teachings of the present invention.

The rolls 12 and 14 may be provided with suitable screw-down mechanisms20 and 22 which may be any one of several known to the art for advancingthe upper roll 12 into a predetermined position with respect to thelower roll 14 to provide a predetermined gap between the rolls topredetermined rolling loads to moisture containing material passingtherebetween. It will be understood that the expression "rolling loads"is defined in this application and the appended claims as the totalpounds or force required to maintain the gap between the rolls throughwhich the moisture containing material passes. The pressures applied tothe upper roll 12 are indicated, respectively, by the pressure gauges 24and 26, respectively. In one embodiment of apparatus of the presentinvention, an additional screw-down mechanism was included, such asadditional screw-down mechanism 30 shown in FIG. 1. The pressure appliedby the additional screw-down mechanism 30 is indicated by pressure gauge32. It will be understood that the screw-down mechanism may be operatedto provide different predetermined gaps between the rolls 12 and 14 toapply different rolling loads to the moisture containing materialpassing therebetween.

The apparatus 10 of the present invention further includes differentialmeans for causing one of the rolls to rotate at a lower speed than thespeed of rotation of the other roll, and such differential means mayinclude any one of several such means known to those skilled in the art.For example, such differential speeds may be accomplished by providingthe rolls 12 and 14 with independent drives or by driving the rolls witha common drive but by providing gearing whereby different speeds ofrotation are imparted to the rolls. In one embodiment of the apparatusof the present invention, differential speed was provided by making theroll 14 of a smaller diameter than the diameter of the upper roll 12whereby upon such rolls being driven from a common source at a commonspeed, differential speeds were achieved.

Upon the wood chips 16 passing between the rolls 12 and 14, they arecompressed as taught above to remove at least a portion of the moisturetherefrom and the particles are reduced in size as indicated by theparticles given numerical designations 36. It has been discovered inaccordance with the teachings of the present invention that upon therolls 12 and 14 operating at differential speeds, the compressedmaterial will adhere to the roll operating at the higher speed, roll 14of FIG. 1, and that the removed moisture will adhere to the rolloperating at the slower speed, roll 14 of FIG. 1. To remove thecompressed particles 36, a wiper 40 may be mounted on the lower roll 14as illustrated diagrammatically to wipe the compressed material from theroll 14 causing the compressed material 36 to fall into the bin 42.Similarly, a wiper 44 illustrated diagrammatically may be suitablymounted to the upper roll 12 to wipe the moisture therefrom forcollection in a suitable container, not shown for clarity of drawingpresentation. It has been further found, in accordance with theteachings of the present invention, that the differential speeds of therollers 12 and 14 will develop friction therebetween which causes therolls to be heated and apply heat to the moisture containing material asit is advanced through the rolls to further remove moisture therefrom byvaporization.

In one embodiment of the present invention, similar to that illustrateddiagrammatically in FIG. 1, the upper roll 12 had a diameter of 6.25inches, the lower roll 14 had a diameter of 5.75 inches, and the rollshad an effective face width of 10 inches; in such embodiment, the rollswere driven from a common source but the diameter differential gave theupper roll 12 a peripheral speed of 114 feet per minute and the lowerroll 14 a peripheral speed of 105 feet per minute. Using such inventionembodiment, various moisture containing materials were passed throughthe rolls with moisture reductions and rolling loads as indicated in theTABLES I, II and III below where column "A" represents initial moisturecontent and column "B" represents moisture content of the mixture afterone pass through the rolls; the temperatures developed in the rolls arealso indicated. It will be understood that the rolling loads in thefollowing tables were computed by dividing the capacity of the hydrauliccylinders (in tons) providing the pressures read by the left pressuregauge 26, center pressure gauge 30, and the right pressure gauge 24 bythe internal pressure at capacity (#/in²) to give the hydraulic cylindereffective area (in²) and by multiplying the hydraulic cylinder pressuregauges (#/in²) and by summing the same.

                  TABLE I                                                         ______________________________________                                        WOOD CHIPS (SOFT MAPLE CHIPS)                                                                                        Rolling                                A     B      Left      Center  Right   Load                                   ______________________________________                                        37%   13%    5000#/in.sup.2                                                                          800#/in.sup.2                                                                         5000#/in.sup.2                                                                        70,114#                                       Rolls Temperature - 300° F.                                     37%   10%    2300#/in.sup.2                                                                          800#/in.sup.2                                                                         2300#/in.sup.2                                                                        35,058#                                       Rolls Temperature - 300° F.                                     37%   06%    3500#/in.sup.2                                                                          900#/in.sup.2                                                                         3500#/in.sup.2                                                                        51,287#                                       Rolls Temperature - 350° F.                                     36%   15%    3000#/in.sup.2                                                                          300#/in.sup.2                                                                         2000#/in.sup.2                                                                        34,407#                                       Rolls Temperature - 70° F.                                      36%   15%    3000#/in.sup.2                                                                          600#/in.sup.2                                                                         3000#/in.sup.2                                                                        42,847#                                       Rolls Temperature - 70° F.                                      36%   14%    4000#/in.sup.2                                                                          1000#/in.sup.2                                                                        4000#/in.sup.2                                                                        58,428#                                       Rolls Temperature - 300° F.                                     ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        VEGETABLE BIOMASS (PEAT)-MIXTURE 50% PEAT                                     AND 50% SOFT MAPLE WOOD CHIPS                                                                                        Rolling                                A    B       Left      Center  Right   Load                                   ______________________________________                                        56%  30%     2500#/in.sup.2                                                                          1000#/in.sup.2                                                                        2500#/in.sup.2                                                                        38,952#                                       Bottom Roll Temperature - 430° F.                                      Top Roll Temperature - 405° F.                                  ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        ANIMAL BIOMASS (COW MANURE) - MIXTURE OF 50%                                  ANIMAL BIOMASS AND 50% SOFT MAPLE                                             WOOD CHIPS                                                                                                           Rolling                                A    B       Left      Center  Right   Load                                   ______________________________________                                        72%  30%     2100#/in.sup.2                                                                          900#/in.sup.2                                                                         2100#/in.sup.2                                                                        27,324#                                       Rolls Temperature - 400° F.                                     ______________________________________                                    

In the following TABLES IV and V where column "A" represents initialmoisture content and column "B" represents moisture content of themixture after one pass through the rolls, no center screwdown mechanismwas used; accordingly, only left and right pressure gauges were used.

                  TABLE IV                                                        ______________________________________                                        HARD WOOD CHIPS (HARD MAPLE,                                                  BLACK CHERRY MIXED)                                                                                                Rolling                                  A    B             Left/psi  Right/psi                                                                             Load/#                                   ______________________________________                                        43%  27%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       306° F. top roll/        134,694                                       199° F. bottom roll                                               42%  7%            5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       421° F. top roll/        134,694                                       233° F. bottom roll                                               32%  17%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       290° F. top roll/        134,694                                       230° F. bottom roll                                               32%  18%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       221° F. top roll/        134,694                                       208° F. bottom roll                                               ______________________________________                                    

                  TABLE V                                                         ______________________________________                                        WASTE WOOD (BRANCHWOOD CHIPS)                                                                                      Rolling                                  A    B             Left/psi  Right/psi                                                                             Load/#                                   ______________________________________                                        47%  30%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       280° F. top roll/        134,694                                       198° F. bottom roll                                               43%  27%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       306° F. top roll/        134,694                                       199° F. bottom roll                                               33%  17%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       290° F. top roll/        134,694                                       230° F. bottom roll                                               42%  26%           5,000-7,000                                                                             5,000-7,000                                                                           96,210-                                       260° F. top roll/        134,694                                       195° F. bottom roll                                               ______________________________________                                    

The percentage by weight of moisture removed from moisture containingmaterial in accordance with the present invention was determined in thefollowing manner: a first quantity of sample of such material, such assoft maple wood chips, was weighed, oven dried, weighed again and thetwo weights compared to determine the initial moisture content of thefirst sample on a percentage by weight basis. Then, a second sample ofthe material was passed through the apparatus of the present inventionand moisture removed in accordance with the process of the presentinvention whereafter the second sample was weighed, oven dried, weighedagain and the two weights compared to determine the moisture content ofthe second sample on a percentage by weight basis after one pass throughthe rolls. Then, the two moisture contents or percentages by weight werecompared to determine the percentage of moisture removed in accordancewith the teachings of the present invention whereby the advantage of thepresent invention was demonstrated.

It has been further found in accordance with the teachings of thepresent invention, and with regard to the removal of moisture containingmaterial having cellular structure, that the differential roll speedsand applied rolling loads develop shearing action which rupture thecellular structure and removes bound moisture contained therein.

Still further, it will be understood that it is within the teachings ofthe present invention to provide a plurality of the apparatus 10 of FIG.1 in tandem whereby the moisture removal process described above may berepeated for further moisture removal and whereby increasingly largerrolling loads may be applied to the material successively and/or higherdifferential speeds may be applied to the successive rolls as thematerial is passed therebetween to create successively greater frictionand successively greater temperatures.

It was discovered that were the rolls 12 and 14 to be operated at thesame speeds, the removed moisture will be pushed back into the roll gapand interfere with the feeding of the material to the rolls. Also, itwas discovered that such removed moisture will propogate to the outeredge of the impacted material where it may be reabsorbed by thecompacted material. However, as taught above, by providing the rollswith differential speeds, the material passed therebetween will beadvanced into the roll gap more readily and the friction will bedeveloped by the slippage between the rolls due to the differentialspeeds.

Referring again to the TABLES, it will be noted that wood chips may beprovided having moisture content well below the 30% referred to in theabove-noted article by Haygreen which wood chips are readily usable forboiler fuel. And, referring particularly to TABLES II and III, it willbe noticed in accordance with the teachings of the present inventionthat while vegetable biomass such as peat is difficult to advancebetween the rolls, by providing a mixture of peat and a carrier materialsuch as soft maple wood chips in various proportions, such as the50%-50% proportions noted in the TABLES, the vegetable biomass and softmaple wood chips mixture will be readily advanced through the rolls toreduce the moisture content of the peat. Similarly, and referring toTABLE II, soft maple wood chips as a carrier may be added to animalwaste, such as cow manure, to readily advance the cow manure through therolls for moisture removal--without the addition of the carriermaterial, it has been found that the advancement of animal wastesthrough the rolls can be undesirably difficult.

It will be understood by those skilled in the art that the examplesgiven in TABLES I-V are merely illustrative but that when suchillustrations are taken in combination with the teachings set forthabove, and as illustrated in FIG. 1, rolling mills of different sizesmay be used to remove moisture from moisture containg materials byup-scaling such rolling mills in accordance with well-known formulas,and it is recognized that upon the present invention being practiced byrolling mills of larger size, different rolling loads will be applied tothe material and different temperatures will be developed in the rolls,all in accordance with the teachings of the present invention.

It has been further found that the apparatus and processes of thepresent invention for reducing the moisture content of the notedmaterials has a further advantage in that the materials upon passingthrough the rolls 12 and 14 are provided with a decreased particle sizewhereby increased surface area is provided which enhances any subsequentfurther drying required or desired.

Additionally, the apparatus and process of the present invention may beadvantageously utilized to de-structure wood biomass and vegetablebiomass in pulping and paper processes. Upon the biomasses beingprovided with increased particle sizes, greater exposed surface areasare provided which facilitate and shorten the digestion time and reducethe amount of chemicals required for the pulping process. Similarly, theincreased exposed surface area provided is also advantageous in themaking of methanol from wood biomass and ethanol from vegetable biomassas the increased exposed surface area also shortens the reaction time ofthe chemical reaction.

Referring again to FIG. 1, it will be understood that instead of usingthe mechanical wipers indicated diagrammatically by reference numerals40 and 44, in the alternative other moisture and compressed materialremoval means may be used such as, for example, suitable vacuum means ofthe type known to those skilled in the art.

With further regard to the above teachings of use of soft maple woodchips as a carrier for advancing peat and animal biomass such as manurethrough the rolls, it has been further found that sawdust and shreddedpaper may be substituted for soft maple wood chips.

Referring again to FIG. 1, it will be understood in accordance with thefurther teachings of the present invention that in the preferredembodiment the slower rotating roll is the bottom roll 14 and the fasterrotating roll is the upper roll 12 to cause the removed moisture toadhere to the upper roll and thereby to prevent the moisture removedfrom the upper roll 12 by the wiper 44 from falling into the compressedmaterial 36.

Referring now to FIGS. 2 and 3, there is shown a further alternateembodiment of apparatus embodying the present invention and in whichfigures structure identical to that shown in FIG. 1 is numberedidentically.

In this alternate embodiment, feed finger apparatus indicated by generalnumerical designation 48 are included to facilitate advancement of themoisture containing material, flowing from the hopper 18, between therolls 12 and 14. As may be best seen in FIG. 2, the feed fingerapparatus 48 is mounted adjacent the input of the rolls by beingsupported or mounted on suitable support structure or brackets indicatedby general numerical designation 47. Feed finger apparatus 48 includespluralities of sets of interleaved feed fingers indicated, respectively,by general numerical designations 50 and 60. Set of feed fingers 50includes individual feed fingers 52, 54 and 56 mounted at their rearwardends on a common bar 51 in turn mounted on a rod 55 mounted reciprocablyin a suitable hydraulic piston 53. Set of feed fingers 60 includesindividual feed fingers 62, 64, 66, and 68 mounted at their rear ends oncommon bar 61 in turn mounted on piston 65 mounted reciprocably in asuitable hydraulic piston 63.

It will be understood from FIGS. 2 and 3 that the sets of feed fingers50 and 60 are interleaved and reside in a common horizontal plane. Itwill be further understood that the hydraulic cylinders 53 and 63 areoperated by suitable control means of the type known to those skilled inthe art to impart alternating reciprocating linear movement to the setsof interleaved feed fingers to facilitate advancement of the moisturecontaining material, flowing from the hopper 18, between the rolls 12and 14.

Referring again to FIG. 2, it will be noted that in this alternateembodiment the upper wiper 44a associated with the faster rotating upperroll 12 is mounted at substantially the top of the roll 12 to increasethe amount of time the compressed material adheres to the lower roll toincrease the amount of time the compressed material adheres to the roll12 to enhance removal by the heat generated by the above-noted frictionof any moisture remaining in the compressed material after rolling andto cause any additional moisture scraped off by the upper wiper 44a toflow down substantially one half of the periphery of the top roll 12 tocause such additional removed moisture to be evaporated by the heat.

Referring now to FIG. 4, there is shown a further alternate embodimentof the present invention wherein the top roll 12 is the faster rotatingroll and the lower roll 14 is the slower rotating roll whereby thecompressed material will adhere to the lower slower rotating roll 14. Inthis embodiment, and a tray 45 is included to catch any moistureremaining in the compressed material adhering to the roll 12 and whichmoisture is removed by the wiper 44b. It will be noted, in accordancewith the further teachings of the invention and as illustrated in FIG.4, the tray 45, being suitably mounted by means not shown, is positioneda predetermined distance d₁ outwardly from the roll 12 to permitcompressed material adhering to the roll 12 to pass between the tray 45and the roller 12 and that the tray 45 is positioned a predetermineddistance d₂ downwardly from the wiper 44b to enhance the falling intothe tray 45 of any moisture removed by the wiper 44b; in one embodiment,d₁ was approximately 1/8 inch and d₂ was approximately 1/4-1/8 inch.

Referring now to FIG. 5, there is illustrated diagrammatically abiodigester embodying the present invention and indicated by generalnumerical designation 100. Generally, the biodigester 100 is forreceiving organic material, such as for example animal biomass, e.g. cowmanure and the like, and is for decomposing or composting the materialby bacterial action or by the action of aerobic microorganisms in thepresence of oxygen, into, for example in the case of animal biomass,organic fertilizer or organic soil conditioner which is sterile, odorfree and weed free.

The biodigester 100 may include a container or vessel 110 provided witha suitable intake 112 adapted to receive organic material such as theabove-noted biomass and a suitable output 114 to discharge thedecomposed organic material. As may be noted from FIGS. 5 and 6, thecontainer 110 may comprise two up-standing side walls, a top and bottom,and opposed ends to laterally contain the organic material such as theanimal biomass and may be provided with conveyor means, such as a firstplurality of laterally disposed screw conveyors 116 (FIGS. 5 and 6)mounted adjacent the bottom of the container 110 and a second pluralityof laterally disposed screw conveyors 118 mounted adjacent the top ofthe container 110 for advancing the organic material through thebiodigester 110 continuously or intermittently as taught below. Inaddition, the biodigester 100 may be provided with a plurality oflaterally disposed air tubes 120 mounted adjacent the bottom of thecontainer 110 below the first plurality of screw conveyors 116 forintroducing an oxygen containing medium such as air into the container110 to facilitate the above-noted decomposition; such air beingintroduced into the air tubes by a suitable blower 122. Further, thebiodigester 100 may be provided with a suitable air vent 128 for ventingthe container 110 to reduce the temperature of the organic material suchas the above-noted animal biomass being decomposed in the biodigester100 upon the temperature of such decomposing material exceeding thepredetermined limit as taught below. In addition, the vent 128 is forbeing closed to cause the temperature within the container 110 to riseand facilitate decomposition as is also taught below.

Referring again particularly to FIG. 5, it will be understood that inaccordance with the further teachings of the present invention thebiodigester 100 may be provided with suitable control means including asuitable microprocessor 130, which may be any one of severalcommercially available such microprocessors, and a plurality of sensors,such as thermal sensors S₁ . . . S_(n) disposed longitudinally, andsuitably mounted within the mass, internally of the vessel or container110. The microprocessor 130 may be suitably interconnected with a motor132, such as a suitable hydraulic or pneumatic motor for operating thepluralities of screw conveyors 116 and 118, with the blower 122 forblowing or feeding air into the plurality of air tubes 120; and with theair vent 128 which may be a suitable motor operated air vent.

An example of operation of the biodigester 100 will now be set forth inthe context of biodigesting, composting or decomposing of dairy cowmanure, but it will be understood that the present invention is not solimited and that such example is merely illustrative of the presentinvention and that other organic materials noted above may be decomposedor digested in the biodigester 100. It will be understood that, inaccordance with the present example, the microprocessor 110 will besuitably programmed in accordance with predetermined parameters, such asthermal parameters, for decomposing the dairy cow manure during a fiveday period as the manure is advanced through the vessel 110 by thepluralities of screw conveyors 116 and 118. Further, it will beunderstood that the microprocessor 130 has been programmed with suchthermal parameters to maintain the temperature within the container 110in the thermophyllic range of approximately 135° F.-180° F. andpreferably approximately 147° F. during decomposition. It will befurther understood by those skilled in the art that the specificprogramming and the specific computer language used are not part of thepresent invention and that upon understanding the invention as set forthherein, such programming may be accomplished by one of ordinary skill inthe art. In accordance with the example of the present invention, freshdairy cow manure is introduced into the vessel 110 through the intake112, the intake and air vent 128 closed, and the microprocessor 130turned on. Natural decomposition will occur through the well knownbacterial action or action of aerobic microorganisms in the presence ofoxygen causing decomposition or composting of the manure with anattendant rise in temperature so long as the aerobic bacteria ormicroorganisms have sufficient oxygen. The thermal sensors S₁ . . .S_(n) will sense the temperature of the various portions of the dairycow manure distributed along the length of the container 110 and, uponthe temperature within the container rising above the above-notedthermophyllic range, the thermal sensors will provide a suitable signalto the microprocessor which will operate the motor driven air vent 128to open the vent and vent the interior of the vessel or container 110 tothe atmosphere thereby lowering the temperature within the container.Upon the temperature within the container falling below the above-notedthermophyllic range due, for example, to reduced or even halteddecomposition activity between the aerobic bacteria or microorganismswhich are oxygen short or deprived, the thermal sensors will provide asuitable signal to the microprocessor which will cause themicroprocessor to close the motor driven air intake 128 permitting thetemperature within the vessel to again rise due to decompositionactivity and in this manner the temperature within the vessel ismaintained within the above-noted desired range. In addition, themicroprocessor will be suitably programmed with parameters for operatingthe screw conveyors 116 and 118 in accordance, for example, with thethermal conditions sensed by the sensors S₁ . . . S_(n) and, in theembodiment illustrated, upon the temperature of the decomposing cowmanure within the biodigester 100 being maintained within theabove-noted range, the microprocessor, for example, will advance thedecomposed dairy cow manure through the biodigester in five days, asillustrated diagrammatically in FIG. 7, by appropriately operatingand/or not operating the screw conveyors 116 and 118 under the controlof the microprocessor.

It will be further understood that in accordance with the teachings ofthe present invention the operation of the biodigester 100 may becontinuous, or substantially continuous, and that upon the biodigester100 being filled with, for example, dairy cow manure as described aboveand operated as noted above, the biodigester will decompose such dairycow manure within, for example, five days and at the end of each fivedays period a predetermined quantity, e.g. one-fifth (20%), of thedecomposed dairy cow manure contained within the biodigester 100 will bedischarged at the output 114 of the biodigester 100 whereupon anotherreplacement quantity, e.g. one-fifth (20%) of the capacity of thebiodigester of dairy cow manure will be introduced into the intake 112and the cow manure will be continuously, or at least substantiallycontinuously, operated for decomposition; this five days procedure isillustrated diagrammatically in FIG. 7. Further, upon the temperature ofthe animal biomass rising above the noted range, and upon themicroprocessor 130 receiving the signal from the sensors S₁ . . . S_(n)to open the vent 128, the microprocessor may turn off the blower 122 tohalt oxygen supply to the bacteria or microorganisms to reduce or evenhalt decomposition to additionally control the temperature of thedecomposing diary manure or animal biomass;o upon the temperaturefalling below the noted range and the microprocessor 130 receiving thesignal from the sensors S₁ . . . S_(n) to close the vent 128, themicroprocessor may turn on the blower 122 to supply oxygen to thebacteria or microorganisms to recommence or accelerate decomposition andadditionally control the temperature of the decomposing animal biomass.

Further, the microprocessor may be programmed in accordance withestablished parameters to accomplish the decomposition in five days bymaintaining the temperature of the decomposing dairy manure or animalbiomass in the noted range by supplying oxygen to the decomposing manurein accordance with a predetermined procedure, e.g. by operating theblower 122 to introduce oxygen, for example at 100 cubic feet per minuteat a static pressure of 10 pounds at 5 minutes per hour, or 21/2 minutesper half hour, or 11/4 minute per 15 minutes.

In summary, oxygen supplied to the decomposing dairy cow manure,maintenance of decomposing manure in a determined temperature range, andthe volume of movement of the manure through the biodigester 100 may beaccomplished under the control of the microprocessor in accordance withthe teachings of the present invention.

It will be understood in accordance with the further teachings of thepresent invention that the oxygen carrying medium, such as air,introduced into the air tubes/plenum 120 may include certain enzymes, orvarious airborne spores, to accelerate decomposition of the organicmaterial, such as animal biomass, e.g. manure within the biodigester100.

In addition, as will be understood by those skilled in the art, dairycow manure upon being deposited by dairy cows has a typical moisturecontent of 70%-85% by weight. It has been found that the efficiency ofthe biodigester 100 may be enhanced by reducing the moisture content ofthe dairy cow manure prior to introduction into the biodigester and inparticular by reducing the moisture content of such dairy cow manure toapproximately 55% by weight.

Further, as is also known, dairy cow manure has nitrogen content anddecomposition of the manure will convert the nitrogen into ammoniaproducing offensive odors which is undesirable and, since nitrogen andits compounds have value, the nitrogen can be undesirably lost in thedecomposition or biodigestive process; it is desirable, therefore, tofix the nitrogen and prevent is conversion into ammonia. In accordancewith the further teachings of this invention, this reduction in moisturecontent and fixing of the nitrogen may be accomplished by mixing carbonwith the dairy cow manure, such as for example in a suitable paddlemixer, in accordance with the well known relationship that approximately35% by weight of carbon having 18%-19% moisture content will absorbapproximately 65% by weight of nitrogen. Using this relationship, and bymixing carbon with the cow manure, the moisture content by weight of thecow manure may be reduced approximately 55% by weight and the nitrogenfixed.

Referring again to FIG. 5, and now specifically to the structure of anembodiment of the container 110 of the biodigester 100 of the presentinvention, it will be noted that the container may be provided with anouter shell of suitable protective material such as metal, or ofsuitable plastic, an intermediate layer of suitable insulation, and aninner shell which may be of a suitable material such as carbon steel,stainless steel, fiberglass or the like. Further, the biodigester 100may be mounted stationarily or may be portable by being mounted on skids150 to facilitate movement from one location to another; alternatively,the biodigester 110 can be mounted on suitable wheels for such portableoperation.

It has been discovered, in accordance with the further teachings of thepresent invention, that the decomposition, composting or biodigestingapparatus and process taught hereinabove may be novelly combined withthe apparatus and processes for compressive rolling to reduce themoisture content of moisture containing material as also taughthereinabove. This novel combination is illustrated diagrammatically inFIG. 8. In FIG. 8 it will be understood in accordance with the furthercombination invention that, for example, animal biomass such as dairycow manure may be introduced into the biodigester 100 and decomposed astaught hereinabove and the decomposed animal biomass output may beintroduced into the hopper 18 (FIG. 1) of the compressive rollingapparatus 10 for compressing rolling to further reduce the moisturecontent of the dairy cow manure. In one embodiment, dairy cow manure isdecomposed in the biodigester 100 and such dairy cow manure, as taughthereinabove, has an input moisture content by weight of approximately72-71% and has the same moisture content by weight after decomposition.But, it has been discovered that upon introducing such decomposed animalbiomass, e.g. dairy cow manure, into the hopper 18 of the rollingapparatus 10, the moisture content may be reduced to approximately 30%providing suitable organic fertilizer or soil conditioner. Further, ifdesired and as also taught hereinabove, the moisture content of thedecomposed animal biomass may be further reduced during compressiverolling by mixing wood chips or saw dust with the decomposed animalbiomass and upon so doing the moisture content of the compressivelyrolled decomposed animal biomass may be reduced 17-15% moisture contentby weight. Further, it will be understood that the combined inventionillustrated diagrammatically in FIG. 8 is not restricted to theprocessing of animal biomass but may also be used advantageously toprocess other materials noted hereinabove.

The biodigester of the present invention, by decomposing manure found onthe typical farm, functions as a new innovative environmental controlapparatus to improve the environment of the farms.

It will be understood by those skilled in the art that many variationsand combinations may be made in the present invention without departingfrom the spirit and the scope thereof.

What is claimed is:
 1. Process for producing organic fertilizer or soilconditioner from moisture containing animal biomass by decomposinganimal biomass by the action of aerobic microorganisms in the presenceof oxygen and by compressing such decomposed animal biomass,comprising:introducing said animal biomass into container means havingan end adapted to receive said animal biomass and an output end adaptedto discharge decomposed animal biomass; introducing a medium containingoxygen into said container to facilitate said decomposition of saidanimal biomass by action of said microorganisms; advancing said animalbiomass through said container means and upon decomposition of saidanimal biomass discharging said decomposed animal biomass out of saidoutput end of said container means; mixing predetermined proportions ofsaid decomposed animal biomass and a predetermined carrier materialchosen from a group consisting of sawdust, shredded paper or wood chipsto enhance the advancement of said decomposed animal biomass betweensaid pair of opposed rolls, said predetermined proportions beingapproximately 50% of each; advancing said mixed decomposed animalbiomass and predetermined carrier material between said pair of opposedrolls to apply predetermined rolling load thereto to compress saiddecomposed animal biomass and remove at least a portion of said moisturetherefrom; and causing one of said rolls to rotate at a predeterminedlower speed than the rolling speed of the other of said rolls to developfriction between the rolls causing said rolls to be heated and applyheat to said decomposed animal biomass to further remove moisturetherefrom, to cause said compressed decomposed animal biomass to adhereto one roll to cause said removed moisture to adhere to said other roll.2. Process according to claim 1 wherein different amounts of air areintroduced into different predetermined portions of said animal biomassas said animal biomass is introduced through said digester by saidconveyor means.
 3. Process according to claim 2 wherein said processfurther includes the steps of sensing the thermal conditions ofpredetermined portions of said animal biomass as said animal biomass isadvanced through said container means and controlling the quantities ofsaid medium introduced into predetermined portions of said animalbiomass in accordance with a predetermined program and controlling therate of advancement of said animal biomass through said container meansin accordance with said sensed thermal conditions.
 4. Process accordingto claim 1 wherein said rolling load is approximately 27,000 pounds. 5.Process according to claim 4 wherein said heat is approximately 400° F.6. Process according to claim 1 wherein said process includes thefurther step of, prior to introducing said animal biomass into containermeans, fixing the nitrogen content of said animal biomass and reducingthe moisture content of the animal biomass to the thermophyllic range ofapproximately 55% moisture by weight, mixing carbon having 18%-19%moisture content with said animal biomass 35% by weight of carbon willabsorb approximately 65% by weight of nitrogen.
 7. Process according toclaim 1 wherein said process includes the further step of including insaid medium containing oxygen a predetermined accelerator to acceleratedecomposition of said animal biomass.
 8. Process according to claim 7wherein said predetermined accelerator is chosen from a group consistingof a predetermined enzyme or predetermined airborne spore.